- 1905 to 19093,215
- 1910 to 19199,319
- 1920 to 192910,067
- 1930 to 193910,209
- 1940 to 194915,869
- 1950 to 195914,959
- 1960 to 196922,615
- 1970 to 197914,271
- 1980 to 198914,377
- 1990 to 199910,535
- 20001,108
The preservation of the Duke University Libraries Digital Collections and the Duke Digital Repository programs are supported in part by the Lowell and Eileen Aptman Digital Preservation Fund